Glass fabricating machines automatically blow a mass of molten glass in a mold to fabricate hot glass articles and then transfer the hot glass article to an oven for annealing. In the period of time between removing the hot glass article from the mold and placing it in the annealing furnace, the glass articles are extremely fragile and susceptible to both thermal and physical damage. Any materials these hot unannealed glass articles touch must be made of materials that will prevent deformation, cracking, or checking of the hot glass. Furthermore, the materials used to handle the hot glass articles must withstand the high temperatures of the hot glass. Stainless steel and other high temperature alloys have been used to handle glass, but metallic materials can cause thermal or physical damage if they contact the hot glass. Therefore, a variety of non-metallic materials have been used to make glass contact material, for example, asbestos, plastics, and graphite. However, each of these materials presents drawbacks to the glass manufacturers.
Although each of the non-metallic materials present problems to its use, graphite is nearly ideal if the problems associated with graphite can be overcome. Although asbestos may be very good for glass handling, strictly from the stand point of its physical properties, its use creates grave environmental and work place safety concerns. Plastics are generally less well suited for high temperature applications and must be specially formulated before they can stand the high temperatures encountered in the hot end process area, and yet they still have a relatively short service life. High quality graphite may be more of an ideal material than others to handle hot glass since graphite has resistance to oxidation, non-abrasive surface integrity, heat resistance, low absorbency and long service life. It is also safe both for the environment and to those who work with it. However, graphite presents several problems that must be overcome before it can be used as a contact material. The first problem graphite presents is that graphite is relatively brittle, which can lead to chipping and cracking. The second problem graphite presents is the difficulty in attaching a graphite contact piece to the supporting body of a fixture, for example, a sweepout arm. Since graphite wears during use, the graphite contact material must be occasionally replaced. Consequently, the article supporting the graphite contact material, or the graphite contact material, must be readily removable, yet the requirement for easy removability frequently results in a supporting body not holding the contact material rigidly and reliably during glass production. The third problem is the need for providing graphite contact material shaped in an array of different shapes and sizes to provide a variety of different fixtures. If these problems could be overcome, then graphite would be ideal for making contact pieces, for example, for the contact pieces used on sweepout arms.
A sweepout arm contacts the hot bottles after they have been removed from a mold and set down on a deadplate, or air pad, to move them from the air pad to a conveyor belt. The bottles then travel to an annealing oven for stress reduction. Therefore, since at least part of the sweepout arm must contact the hot glass, the sweepout arms frequently include non-metallic contact materials mounted on a metallic base plate for contacting the hot glass. Although graphite is the best of the non-metallic materials for contacting hot glass directly, the problems of graphite's brittleness, the difficulty in attaching it to the base plate and the need for a variety of different shapes and sizes of precision machined graphite parts make graphite difficult to use for sweepout arm contact materials.
Therefore, a sweepout arm could advantageously include modular, single size and shape graphite contact members. These members would be rigidly and reliably mounted on the sweepout arm base plate. Such graphite contact plates would ideally be readily replaceable in the event of wear or damage to permit the replacement of the contact material instead of the entire fixture. Making the sweepout arm of modular members would allow only a minimal inventory of sizes and shapes of contact material to be used for all sweepout arms.